Clamping fixture



Sept. 4,

C. L. OTT

CLAMPING FIXTURE Filed Sept. 11, 1942 3 Sheets-She CONRAD L- OTT etl lhwcntor Gttorncg Se t. 1945.

c. L. QTT

CLAMP ING FIXTURE Filed Sept. -11, 1942 3 Sheets-Sheet 3 3nventor CONRAD L. 0 7'7 (Ittorneg Patented Sept. 4, 1945 Conrad L. Ott, Detroit, Micln, assignor to Landis Tool Company, Waynesboro, Pa.

Application September 11, 1942, Serial No. 458,032

2 Claims.

My invention relates to work clamping devices, particularly of the type used to hold crankshafts during a machining operation.

It is an object of my invention to provide a device for clamping crankshafts which will make use of a sliding clamping element.

A further object is to provide power means for opening and closing said clamping fixture.

A further object is to provide a torque type fluid motor for actuating said clamp.

A further object is to utilize the fluid under pressure for driving said motor, to lubricate the spindle bearings.

A further object is to provide means whereby failure of pressure while a work piece is held by the clamp will not result in release of said Work piece.

Figure 1 is a front elevation of a crank grinding machine using my clamping device.

Figure 2 is a sectional plan view of a crank head showing the clamping motor and the fluid passages leading to same.

Figure 3 is an end elevation partly in section of the clamping mechanism.

Figure 4 is a sectional elevation distorted to show the gearing for driving the clamping mechanism.

Figure 5 is a piping diagram.

Numeral l indicates the bed of a grinding machine, H a Work carriage slidably mounted thereon, l2 and I 3 the left and right heads respectively, and I4 a work piece held by clamps on said heads. A motor l mounted on head l2 drives thru a chain to sprocket I6 on shaft ll.

Said shaft provides a common drive means for Sprocket I8 on said shaft drives both. heads. thru chain iBA to sprocket I9 on each of the spindles 32.

A grinding Wheel is rotatably mounted on a wheel support 2| movable transversely toward and from said work piece. The grinding wheel may be driven by any suitable means such as a motor or jackshaft, neither of which is shown. A handwheel 22 serves to adjust or feed the wheel support toward and from the Work.

Each of the heads l2 and i3 consists of a housing in which are mounted spaced bearings and 3! for rotatably supporting a spindle 32. In each of said spindles are two fluid passages 33 and 34; said passages have radial portions 23 and 24 in alignment with circumferential grooves 35 and 35 in bearings 35 and 3| respectively. An end plate 37 secured to the end of spindle 32 is bored to provide continuations of said passages. A portion of said end plate extends in a direction parallel to the axis of said spindle and provides a base to which is secured a reversible hydraulic torque motor 40. From said plate-fluid may be conducted by any suitable means such as pipe or tubing to said motor. Fluid under pressure may be introduced into passages 33 and 34 from any suitable source as will be described later. The driving shaft 4| of said motor extends axially thru spindle 32. The end of said spindle opposite said motor is flanged at 38 to provide space for mounting a clamping mechanism. On the flange end of shaft 4| is a pinion 42 which drives a large idler gear 43. Said idler is mounted integrally with a pinion 44 which in turn engages a gear 45. Said gear 45 is mounted on the end of a shaft 46. At the other end of shaft 46 is a pinion 41. Said pinion engages rack teeth 50 on a slidable clamping member 5| having a cam surface 53 for engaging tangentially the surface of i4. Said member is mounted on said flanged portion in guideways 52. A block 55 is mounted eccentrically on an axially extending portion of flange 38 and has a cylindrical recess 56 for receiving the end main bearing of a crank shaft M.

A notched disk 60 rotatably mounted in flange 38 is a well known means for indexing crankshafts. A latch 61 is urged into engagement with said notches by spring 62. A lever 63 serves to withdraw said latch against the action of said spring.

In operation a work piece I4 is placed in the recessed members 55. The operator shifts lever 10 to the right and fluid under pressure from pump ll passes thru line 12 to valve housing 13 where valve piston 14 directs it to passage 15. From passage '55 said fluid is distributed thru passages 33, 1B and H and the passage in plate 31 to motors 4U. Said motors then rotate in a direction to shift the clamping members 5| to clamping position. To release the work, lever 10 and valve 14 is shifted to the left to direct fluid thru passages 34, I8, 19, and 8D and the passage in plate 31 to said motors 4B. When fluid is directed to the motors thru these passages, said motors rotate in a direction to withdraw said clamping member and thus release work piece 14. Since it is necessary to apply fluid under pressure to withdraw the clamps, no special safety device is needed. The clamping mechanism is in effect self-locking. In the event of pressure failure while work is in the clamps, said clamps will simply remain in work gripping position. This is a much simplier type of positive lock than is disclosed anywhere in a prior art.

porting and rotating member, including a spindle 10 supported in spaced bearings, a clamping fixture on said spindle, power means for operating said clamping fixture including a fluid pressure operated motor also mounted on said spindle,

means for introducing fluid under pressure to '15 said bearing, and passages in said spindle for conducting said fluid to said motor. I

2. In a metal working machine, work holding and rotating members, each including a spindle rotatably mounted on spaced bearings therein, a Work clamping member on one end of said spindle comprising a block for supporting a work piece, a member slidable tangentially of the work and having a cam surface for clamping said work piece in said block, rack teeth on said member, a pinion for engaging said rack teeth, a shaft extending axially thru said spindle, connections from said shaft to said pinion, and means for rotating said shaft.

CONRAD L. O'I'I. 

